Centimeter accurate global positioning system receiver for on-the-fly real-time kinematic measurement and control

• US 5,757,646 A
• Filed: 11/07/1996
• Issued: 05/26/1998
• Est. Priority Date: 02/18/1994
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Talbot, Nicholas Charles, Nichols, Mark Edward, Allison, Michael Timo
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/745,579
• Time in Patent Office: 565 Days
• Field of Search: 364/449.7, 364/449.9, 364/424.029, 364/460, 364/423.099, 364/424.028, 342/357, 342/457
• US Class Current: 701/215
• CPC Class Codes: G01S 19/04 providing carrier phase data
• CPC Class Codes: G01S 19/32 Multimode operation in a single same satellite system, e.g. GPS L1/L2
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

A system embodiment of the present invention comprises a fixed and a roving pair of four-observable GPS receivers and a communication link between them for double differencing code and carrier measurements. Carrier phase integer ambiguities are resolved efficiently by searching the simultaneous narrow-lane intersections of both the L1 and L2 wave fronts propagated by the GPS satellites being tracked. External constraint information, such as elevation, is additionally used to speed up integer ambiguity resolution. Data between the reference station and the rover is communicated in compressed form at a regular interval, e.g., once a second at each epoch, and demi-measurements of carrier phase are obtained more frequently, e.g., ten times a second, and used to propagate solutions between epochs.

Claims

1. A control system, comprising:

an on-the-fly real-time kinematic (OTF-RTK) global positioning system (GPS) reference station configured to provide RTK GPS data;

a remote unit including a communication device and a GPS receiver coupled to said communication device, said communication device configured to receive said RTK GPS data and to transmit positioning information generated by said GPS receiver at an update rate of 10 Hertz or more;

a central control unit having a stored virtual model of an operating site, said virtual model including one or more attributes of said operating site, said central control unit configured to receive said positioning information, to compare said positioning information with said attributes from said virtual model and to issue control signals to said remote unit in response thereto.

2. A control system as in claim 1 wherein said remote unit is fitted to a vehicle.

3. A control system as in claim 2 wherein said remote unit further comprises a control unit configured to respond to said control signals by guiding said vehicle.

4. A control system as in claim 3 wherein said control unit is a servo unit.

5. A control system as in claim 4 wherein said virtual model represents at least a portion of a topographic survey of a coal seam.

6. A control system as in claim 5 wherein said vehicle is an open pit coal excavator.

7. A control system as in claim 4 wherein said servo unit controls a guidance mechanism of said vehicle.

8. A control system as in claim 3 wherein said vehicle is an unmanned vehicle.

9. A control system as in claim 8 wherein said control unit is a servo unit.

10. A control system as in claim 3 wherein said virtual model represents a placement for a piling.

11. A control system as in claim 1 wherein said remote unit is further configured to provide demi-measurements at a rate more frequent than said update rate, said demi-measurements being used to compute said positioning information.

12. A computer assisted method of controlling a remote vehicle, comprising the steps of:

transmitting real-time kinematic (RTK) global positioning system (GPS) data from an on-the-fly real-time kinematic (OTF-RTK) GPS reference station;

receiving said RTK GPS data at a vehicle fitted with a remote control unit having a GPS receiver coupled to a communication unit configured to receive said RTK GPS data and to communicate with a central processing unit;

transmittiing positioning information generated by said GPS receiver to said central processing unit at an update rate of 10 Hertz or more;

comparing said positioning information with vehicle guidance information stored at said central processing unit and generating control signals in response thereto; and

transmitting said control signals to said vehicle.

13. A method as in claim 12 wherein said vehicle responds to said control signals by altering its path.

14. A method as in claim 12 wherein said remote control unit further has a control unit configured to receive said control signals and said control unit responds to said control signals by controlling the guidance of said vehicle accordingly.

15. A method as in claim 14 wherein said control unit includes a servo unit.

16. A method as in claim 15 wherein said servo unit controls a guidance mechanism associated with said vehicle.

17. A method as in claim 12 further comprising the step of updating said positioning information with demi-measurement updates at a rate more frequent than said update rate prior to transmitting said positioning information to said central processing unit.

18. A vehicle control system, comprising:

a central processing unit configured to communicate with an information system including a virtual model of vehicle guidance plan and to generate vehicle command signals, a communications unit coupled to the central processing unit, and an on-the-fly real-time kinematic (OTF-RTK) global positioning system (GPS) reference station coupled to the communications unit and configured to provide RTK GPS data thereto for transmission; and

a vehicle including a GPS receiver, a communication device coupled to the GPS receiver and configured to receive said RTK GPS data and to transmit positioning information generated by the GPS receiver to said central processing unit at an update rate of 10 Hertz or more.

19. A control system as in claim 18 wherein said vehicle further includes a control unit configured to receive said vehicle command signals and to control an operation of said vehicle in response thereto.

20. A control system as in claim 19 wherein said control unit is a servo unit.

21. A control system as in claim 19 wherein said vehicle command signals comprise vehicle guidance information and said control unit controls the guidance of said vehicle in response thereto.

22. A control system as in claim 21 wherein said vehicle is an aircraft and said vehicle guidance plan comprises a flight plan for said aircraft.

23. A control system as in claim 18 wherein said GPS receiver is configured to update said positioning information with demi-measurements at a rate more frequent than said update rate.